Apple scab first appears as small, olive-colored lesions on the undersides of the leaves. As the fungus spreads, the top sides of the leaves develop lesions, as well, that may become black or mottled with defined edges. Severely infected trees may become defoliated by mid-summer, making the tree vulnerable to other diseases. The fruit develop black or brown scabs or soft areas.
cytosis. [ 1 sÄ«tÅâ²sis] 2  a condition in which there is a greater than normal number of cells in a tissue or organ.
Apoptosis (from Ancient Greek á¼ÏÏÏÏÏÏÎ¹Ï falling off) is a process of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death.